


Behind Bones

by zeo_nulla



Category: Undertale (Video Game)
Genre: Alternate Universe - Magic, Big Brother Sans (Undertale), Found Family, Gen, MAGIC AND ADVENTURE, Magic Sans, Muteness, Nonbinary Frisk (Undertale), Not evil flowey, Other Additional Tags to Be Added, Speaking in "hands", Underfell elements, Unstable Toriel, magic frisk
Language: English
Status: In-Progress
Published: 2021-02-21
Updated: 2021-02-21
Packaged: 2021-03-17 22:53:56
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,398
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29599968
Author URL: https://archiveofourown.org/users/zeo_nulla/pseuds/zeo_nulla
Summary: He looked up, expecting to see matted white fur, eyes yellowed by overexposure to smoke from fire magic, a mouth full of sharp teeth telling him to buzz off for the thousandth time.He didn’t see any of that.Instead, he saw a small figure at the bottom of the doorway, holding it open slightly. Their face the skull of a fawn.They extended a tiny hand to him and held out a yellow flower for him, the same as the crowns placed on the bags.
Relationships: Flowey & Frisk (Undertale), Frisk & Papyrus (Undertale), Frisk & Sans (Undertale), Papyrus & Sans (Undertale)
Kudos: 10





	1. Shaky first steps

The light of a Red moon above fills you with determination.

Enough to flee from the screams and blood, the sound of weapons clattering and the heavy scent of copper, blood. Two large clawed hands press to your back, egging you onward. You need to flee, the pack is dying.

You run and run, it is an uphill battle. You see the pillar of blackened smoke as you Crest the horizon.

Another step as you hear shouts getting closer, a spear whizzing past your hooded face. You step forward again.

And are met with nothing to catch yourself.

You fall, the Red moon the last thing you see as you tumble into the mountainside.

* * *

He was not big into the talk he often got from his little brother...his little 'lieutenant of the guard so you have to listen to me.' Little brother. Though, little more applied to him, stunted by Monster standards and standing at around seven foot give or take, maybe eight. Taller than most humans but still shorter than the norm. 

He let out a sigh. The bright red fur around the hood of his black robe doing little to make him feel any warmer when his soul felt cold and blue.

He missed the ones still on the surface, but even if any fell, if any came...he would never know if not for contact with the former queen.

She let them know, she gave reports, but never said whether or not humans fell.

It made him upset. He grit his fangs together and clenched the basket he held in his hands tightly, joints popping. The walk from snowdin to the door was agony, even as a supply run. Why was this woman being pampered while her husband lay bedridden? Why did she get to flee from the responsibility of the half breeds who gave their souls to the king to punch a small, slowly decaying hole through the barrier? She was the reason his brother had to work so hard. She was the reason they did not get fresh meat. She ate the animals that fell into the ruins and tossed the bones just outside the door. She also set out bags of dust. Smaller monsters often went out on scouting parties to the above, they could fit through the gap in decaying magic.

Sadly, that did not ensure safety and the humans, like the spiteful creatures they were, would not allow even the Dust of monsters to rest on the surface, bagging and dumping it back into the mountain immediately.

Even though he disliked her, he hated humans too. Pap never got to see the stars like him. He had just been a baby bone. 

He had never learned the difference between human and half-breed.

He never got to meet the Witch before she was burnt alive, or the old man.

Pap could barely speak in hands, just shy of the fluency that sans had.

The basket of magically produced food made him sigh.

They had figured out synthesizing early on, he had his old man's notes after all...but it felt wrong to take up the mantel of head Sorcerer from his dead caretaker.

He left it to Alphys, her knowledge of alchemy was nothing short of brilliant.

After the war, he just. He could not bring himself to care much. Everything was too heavy and painful. His brother was kind, he gave him one of the least taxing jobs as a scout. It meant chasing off Ferals every so often, but he could handle that. He hated his every-other-day supply runs to the queen.

He felt angry delivering her food for some reason.

Coming up on the door he paused.

There were three burlap bags hung on a metal pole, it was here as a delivery station. Sans knew that, that was not what was bothering him.

It was the little golden flower crowns placed on each bag.

Gritting his teeth tighter until pain seeped into his skull and his red eye light flared, dripping red smoke out from the socket as he banged on the door.

How dare she act like she cared so nonchalantly after all this time?

"You better come out here and explain this old lady!" 

He hissed through gritted teeth. The door cracking open slightly.

He looked up, expecting to see matted white fur, eyes yellowed by overexposure to smoke from fire magic, a mouth full of sharp teeth telling him to buzz off for the thousandth time.

He didn’t see any of that. 

Instead, he saw a small figure at the bottom of the doorway, holding it open slightly. Their face the skull of a fawn.

They extended a tiny hand to him and held out a yellow flower for him, the same as the crowns placed on the bags.

* * *

This was not real. There was no way a baby-bones like this could be hidden in the ruins.

He eyed the little thing and set down his delivery basket.

It still held the flower out to him, silent as a sentinel. A thought struck him. The old man saying most skeletons could not speak without strong magic. Shakily he signed in hands.

_'_ _What brat?_ _'_

A couple of things happened.

The child raised the flower up and then gestured with one hand for him to take it.

…

Speaking in hands.

With body language thrown in. Sure it was crude, a basic level even Papyrus would have understood, but it got the point across. He begrudgingly took the flower.

He looked at the black-gloved hand...dirty, like their cloak and pants and footwear. Not an inch of them uncovered, not an inch of them not dirty.

Even their skull was, a thin layer of dirt forming over what should be pure porcelain white.

He opened his mouth to speak before an unholy hissing stopped him and thorn-covered vines erupted around the door.

**"Back off smiles."**

He had to, just to avoid being hit mind you. Still, he would be rolling eyes if he had them. He could hear the slight quiver in a forced aggressive tone.

The child though...they ended up covered in vines and pulled away from the door before it slammed shut.

He sighed rubbing the back of his skull and gathering up the dust bags.

He looked at the flower that had fallen from his fingertips in the sudden commotion and with a derisive snort turned away from it.

Only to reach down and pick it up with a curious eye before leaving the delivery behind.

He had learned something very interesting today.

* * *

"What do you THINK you were doing?"

The flower constricted around them, the thorns were gone for now, but they did not like the idea of this hold. Flowey was prone to mood swings, not as violent as...the caretaker, but still violent over the idea of them leaving.

They felt bad for the lonely monster woman and the lonely flower.

They knew the feeling. But the voice on the outside had wanted the door to open, so they did as they were told.

The monster on the outside of the door spoke to them in the way the pack had.

Even if he called them a brat…

It filled them with determination to see that monster again.

"...AND if anyone figures out what you are, you are straight-up DEAD you understand kid? You are something that can be eaten and used as the final push to destroy the barrier. Others like you already have died to help do that...but no one knows the difference anymore."

Huh, Flowey was doing that thing again, where he spoke at the ground and his petals began to droop. They carefully freed an arm and reached out. Delicately stroking Flowey's petals.

"I...I don't want you to die...if you try to leave she might actually try to kill you."

Their heartaches. Even though they are being held prisoner here by a woman insisting that they are her child...Flowey is just as much a prisoner as them, trapped because he can't bear the thought of the only being to be kind to him would get murdered in some horrific way.

He stays with them and they can show him their true face. He said they were cute. It made them smile more than the memory of when the pack freed them.

Carefully they draw on the dirt with one of the bones left lying around. Flowey likes it when they do this. Because most monsters use words for incantations...but being the way they are, they had to find other ways.

Sure, they can't do much, but Flowey likes this one.

It always cheers him up.

A gentle burst of light as the sun-bug spell ignited to life. Slowly, dozens of little lights pulse into existence and slowly fade into other colours and shades, as if the beat of it changed with some invisible music. They both watched, huddled against each other, emotionally drained as sleep took them and the lights faded out.


	2. Flowers and Skulls

**Summary for the Chapter:**

> The way the creature curled around the child and the way that the kid was softly trying to soothe the flower with gentle touches...he knew. This was similar to how he and Pap used to be. Pap was not...much of a talker, he was always worried over what to say, so sans would stand up for his brother when someone got in his business. always brash to a fault.   
> Pap would patch him up after, not speaking, but offering soft rattling and warm eye glowing.  
> He was stoic because he had troubles with emotions, it did not make him any less kind.

He was holding his skull in his hands, staring at a wilted flower and having an internal debate with himself.

Not his best moment, but when you are a depressed aggressive skeleton monster, you take what you can get for moments of tranquillity. But at the counter of Grillby's tavern...while everything was still quiet and his friend was cleaning out the Bierkrug's 

He had to mull over his options.

First: he let things lie. He could just leave the kid in the ruins and never talk about it...his non-existent guts clenched thinking back to how small they were...stunted, a word he knew all too well from his first years being used to feed a baby brother when it was just the two of them in the world after a human attack.

If he left them….they could end up as a dust bag...he would never know.

Option two was to tell his brother, get the kid forcibly removed. And like all monster children without parents due to them going feral or dying due to complications they would live as a squire. A young helper to the guard. They would learn and grow in a regimented environment….but they would be safe as all children who join the guard are taken care of very well and become an interlocked family with all the monsters within.

But…

They couldn't speak. What would the other monsters do? They...they would become an outcast among them...no doubt.

He tapped his distal phalanx's across the dark red stone of the counter, a type of granite no doubt. He would make a pun about it, but given his current mood, he'd take it for granite. His eye lights zeroed in on the wilted flower again.

What was he gonna do? What COULD he do? There was a crazy ex-queen on the other side of that door...he could not afford to piss her off...and yet…

Memories of little arms holding out the flower and not even trying to fight back when he was rude flooded him.

He could...for now, check on the kid...somehow. he could make more regular trips to the door at the same time and check to see if they were there. Getting yelled at by the old lady was nothing new so that he could handle.

He carefully picked up the little golden flower.

Huh...the same kind in the ruins as there were in the palace gardens.

And it had been given to him.

Muttering under his breath he pulled a journal out from his robe and placed it between two blank pages.

"Gonna have to document this, baby bones."

\---

They perked up as they heard a knock. The caretaker told them to wait by the door and let them know if anyone came, they did this dutifully and without leaving the door with the threat of being hunted and burned alive. But when the door was knocked on it sparked hope in them. Maybe they could be saved from this small claustrophobic space. Flowey was sure that no one would help. That anyone who came to know them truly would only mean harm.

They stubbornly refused to believe that. From what the pack had said to them, monsters were good, unjustly thrown into this place. The humans had said differently, but they were less inclined to believe those stories. Who would believe the ones who inflicted harm?

With all the might they could muster they pushed the door open just a crack.

"Hey there baby-bones." 

They were greeted with a rough voice...rough in the same way a roaring fire was, the voice held power, wrath...but warmth bubbled in it too.

It was the skeleton!

Their body vibrated and they picked up one of the bones they had carved that looked a little like him. They had carved many to look like flowers so that the hall looked less like a pit of death and more like a garden.

But this one was special. They had been so excited they had carved it just for him.

Shakily they held it up to the massive skeleton. He...he looked kinda what humans would call the 'grim reaper' in that big billowing cloak. But he was broad, if he had musculature they would have no doubt said he was muscular. Red-eye lights focused on them and it did not make them afraid.

It reminded them of the moon the night they fell. Beautiful and red, watching over them all.

"Huh...this for me?"

They nodded then remembered that this monster could speak like them and signed the affirmative instead.

Stars, it was so nice to be understood when speaking again.

\---

He turned the figure over in boney fingers, taking it in as the kid peered at him curiously. Without eye lights, it was hard to tell where they were looking, but their attention seemed to be entirely on him.

The thing he held was made of bone, worn and shaved into a little figure that looked crudely like him. It was clearly a child's rendition. He huffed out a laugh. Kids were weird, he guessed. He reached out to pat the child on the head and was shocked when they ducked down and covered their head with their arms.

Were they afraid of him?

"Kid, I'm not gonna-Fuck!" 

He cursed out as a thorn shot between him and the kid, the creepy flower winding around the kid and glaring at him.

"Back off!! Can't you see they don't like hands trying to grab them?"

Sans gritted his teeth, ready to cuss out this annoying weed...but…

"H-hey, it's okay, no one's gonna hurt you. I gotcha, I promised I would keep you safe."

Fuck, shit, shit. The kid was shivering looking down. It...it was not him. They were probably scared of anyone trying to grab at them.

"Hey...I uh, I was just gonna pat ya on the head kiddo...um. if it helps next time I will warn ya?"

Dear Asgore, he wished his voice was not so deep and rough for once in his life...but after a good five minutes his words seemed to register to them and they signed to respond.

'Yes please.'

He found himself rubbing behind his skull, it had been a while since he had dealt with a kid...but, pap had never been this anxious. What had happened to this kid?

What was the old lady doing to this kid?

"Hey, don't be upset kid, my heart can't take it."

There was a beat of silence and then the kid was shaking, but this time in silent laughter as they gave him a thumbs up after and the flower groaned.

Sans grinned even wider

"Groan all you want weed, you can't get under my skin." 

More silent shaking and thumbs up and a long aggravated sound of frustration from the weed.

"Heh, knew I liked ya for a reason kid...so. what is a baby-bones like you doing in the ruins?"

The kid signed a few different things

'Caretaker' 'fire' 'watches' 'kills' 'fell'

It...was hard to interoperate.

The flower sighed and began to softly whisper to the child...something about that flower, sans didn't like it.

"So, they trust you, which I think is dumb but hey they are weird like that...plus you understand them so…" 

The kid was nodding a whole lot at the flower. It was a weird one-sided conversation. It was weird how the flower just seemed to know what the kid was saying.

Sans immediately didn't trust it.

"Look, I think you have some kind of play. You are wearing a uniform under your cloak, sloppy as it is. That means you work for the royals. That extends to the queen. So I already don't trust you. But here is the long and short of it: I found this kid in the ruins in really bad shape. We worked together to survive for around two months...the spiders and froggits helped us out….then the queen found us."

The kid gently patted the petals of the slowly drooping flower who...honestly looked like it might cry.

"Sh-she is pretending they are her kid...she is always going from very sweet to...something else. She says if they ever try to leave her like the others did...she will...burn them alive and keep their dust instead." 

Sans...was a little shocked. The queen had taken the sacrifice of the half-breeds hard, she had lost her son to the humans and then she lost all the half breed's she had come to adopt since falling...but they had made that choice long ago. They wanted to help. They gave their souls and magic willingly. It was so long ago that no one would know a half breed from a human anymore, not like there were any left. They had to have been hunted to extinction or used as tools of humans like the mages that erected the barrier in the first place.

It was a pitiful fate for creatures like them...he remembered the nervous child clinging to the witch and watching as she brewed potions.

The kid was amazing at telling fortunes, even if he was blind in one eye, he could read tea leaves very well.

Sans shook the thought away. That kid was long dead by now.

"So...the kid can't leave. Why are you staying weed?"

Truthfully it piqued his curiosity.

"I...I don't have to tell you anything!"

But the way the creature curled around the child and the way that the kid was softly trying to soothe the flower with gentle touches...he knew. This was similar to how he and Pap used to be. Pap was not...much of a talker, he was always worried over what to say, so sans would stand up for his brother when someone got in his business. always brash to a fault. 

Pap would patch him up after, not speaking, but offering soft rattling and warm eye glowing.

He was stoic because he had troubles with emotions, it did not make him any less kind.

And it seemed these two had a similar dynamic. The thought alone freed a chuckle from him.

"Well...I have to go. But here's the deal. I will try to come by every day at the same time. I will bring you food, or whatever else you may need. In return, we chat okay? Maybe fix up your hand talk...it is pretty basic kid."

He got up and let his bones settle watching the flower stare at him as he rose.

"What? That's it?"

He snorted derisively.

"Look, _Bud._ I may not want to _leaf_ but I have a job. Plus, it is not like I can break you out. I am just a sentry, you said it yourself. I work for the royals, even if I hate it...that being said. I'm not gonna just let this keep going on...but first the kid needs to be stronger. We will talk plans and escapes then."

The child...was flapping their arms, fully excited. They must be happy with that. They kept showing smiling gestures with their hands and it was...cute.

Asgore help him, he was so screwed.

**Notes for the Chapter:**

> Whooo boy! expect that fun world-building in between all the strange feelings our poor nervous skelimage has had thrust upon him.   
> Sans: ...The fuck is this?  
> Frisk: Exists  
> Sans:...  
> Sans: *Frantically filling out adoption forms*   
> If you wanna see the reference for our little protagonist it is right [Here](https://zeoumren.tumblr.com/post/643779514163429376/a-secondary-reference-for-my-story-behind-bones) and if you want to just drop me an ask to talk about this AU then you can find my tumblr by following this [Link to my tumblr](https://zeoumren.tumblr.com/)  
> Until next time my Dear Boo's! ♡

**Author's Note:**

> Wooo! Here is the prologue to my first work in this fandom. I have been scared of it for a while, But I do love undertale so I want to bring something to it as well.  
> If you want to check out my singular character reference for this it is over here: [Behind Bones Sans](https://zeoumren.tumblr.com/post/643584116821049344/ah-yes-my-very-nervous-magical-bone-man-i)  
> And if you want to ask me something about this AU then please drop me an ask!  
> [My Tumblr](https://zeoumren.tumblr.com/)


End file.
